1. Technical Field
The present disclosure relates to all-reflective optical systems, and particularly to an off-axial three-mirror system.
2. Description of Related Art
All-reflective optical systems have long been the champions of the astronomical community, primarily because of their small size, lightweight construction and broad spectral coverage. One type of all-reflective optical systems is an off-axial three-mirror system, which includes a primary mirror, a secondary mirror, and a tertiary mirror.
In some related art, spherical mirrors and conicoid mirrors such as ellipsoidal mirrors, parabolic mirrors, and hyperbolic mirrors are employed in the off-axial three-mirror system. There are not many degrees of freedom in said mirrors that the off-axial three-mirror system cannot provide a superior performance in imaging.
Another problem in some related art is the assembling and aligning of the mirrors, for the primary mirror, the secondary mirror, and the tertiary mirror in the off-axial three-mirror system are all separate from each other.
What is needed, therefore, is to provide an off-axial three-mirror system, in which the mirrors have more degrees of freedom, and the mirrors are easier to be assembled and aligned.